Cell division is one of the most fundamental events for self- reproduction of living organisms together with DNA replication, and membranes are one of the most essential structures of living organisms, although little is known about them. Study of cell division and membrane proteins can be expected to have broad implications with respect to understanding not only the processes of normal growth but also those resulting in uncontrolled growth such as is found in cases of cancer. Our long term goals are: (a) to solve the control mechanism of bacterial division - precise sequence of events leading to cell division, involving positive and negative regulatory factors and constituents of septum, (b) to solve the mechanism of the initiation of DNA replication and its relationship with cell division, (c) to solve the assembly mechanism of the membranes of Escherichia coli and the relationship between membrane proteins and cellular activities such as cell division and DNA replication, and (d) functional and structural characterization of a lipoprotein of the E.coli outer membrane, as a model system of biochemistry of membrane proteins. Bibliographic references: N. Ohta, R. Sager, and M. Inouye. Identification of a chloroplast ribosomal protein altered by a chloroplast mutation in chlamydomonas. J. Biol. Chem., 250, 3655-3659 (1975). M. DeMartini, S. Halegoua, and M. Inouye. Lysozymes from bacteriophages T3 and T5. J. Virology, 16, 459-461 (1975).